论文标题
质子中的光夸海的风味不对称测量，$ p+p $和$ p+d $ collision
Measurement of flavor asymmetry of light-quark sea in the proton with Drell-Yan dimuon production in $p+p$ and $p+d$ collisions at 120 GeV
论文作者
论文摘要
质子中的$ \ bar u $和$ \ bar d $ Quark分布之间的风味不对称的证据已在深度无弹性散射和Drell-Yan实验中发现。这种风味不对称的明显依赖性对$ x $（Partons携带的核素动量的一部分）的明显依赖性在Fermilab E866 Drell-Yan实验中观察到，这表明$ \ bar d \ weft（x \ right） / \ bar u \ weft（x \ bar u \ weft（x \ right）$ x 0.15 $ x 0.15 $ x 0.15 $ x 0.15 $ x 0.15 $。我们报告了Seaquest Fermilab E906实验的结果，其统计精度提高了$ \ bar d \ left（x \ right） / \ bar u \ left（x \ right）$在大的$ x $区域中，最高$ x = 0.45 $，使用120 GEV Proton Beam。从seaquest数据中提取$σ^{pd} /2σ^{pp} $的两种不同的方法，从seaquest数据中得出一致的结果。 $ \ bar {d} \ left（x \ right） / \ bar {u} \ left（x \ right）$ ratios和$ \ bar d \ left（x \ right） - \ bar u \ left（x \ first）$差异是从这些横截面率中获取的，价格为0.13 <x <x <x <x <x <x <x <0.45 $ 0.13 <x <x <x <x <x <0.45 $。 SEAQUEST和E866 / NUSEA $ \ bar {d} \ left（x \ right） / \ bar {u} \ left（x \ right）$比率与$ x \ lyssim 0.25 $区域非常同意。但是，新的SeaQuest数据表明，$ \ bar d \ left（x \右）$继续大于$ \ bar u \ weft（x \ right）$，最高$ x $ value（$ x = 0.45 $）。 $ \ bar {d} \ left（x \ right） / \ bar {u} \ left（x \ right）$和$ \ bar {d} \ left（x \ right） - \ bar {u} \ left（x \ right）$与各种党派分布函数和理论计算进行比较。
Evidence for a flavor asymmetry between the $\bar u$ and $\bar d$ quark distributions in the proton has been found in deep-inelastic scattering and Drell-Yan experiments. The pronounced dependence of this flavor asymmetry on $x$ (fraction of nucleon momentum carried by partons) observed in the Fermilab E866 Drell-Yan experiment suggested a drop of the $\bar d\left(x\right) / \bar u\left(x\right)$ ratio in the $x > 0.15$ region. We report results from the SeaQuest Fermilab E906 experiment with improved statistical precision for $\bar d\left(x\right) / \bar u\left(x\right)$ in the large $x$ region up to $x=0.45$ using the 120 GeV proton beam. Two different methods for extracting the Drell-Yan cross section ratios, $σ^{pd} /2 σ^{pp}$, from the SeaQuest data give consistent results. The $\bar{d}\left(x\right) / \bar{u}\left(x\right)$ ratios and the $\bar d\left(x\right) - \bar u\left(x\right)$ differences are deduced from these cross section ratios for $0.13 < x < 0.45$. The SeaQuest and E866/NuSea $\bar{d}\left(x\right) / \bar{u}\left(x\right)$ ratios are in good agreement for the $x\lesssim 0.25$ region. The new SeaQuest data, however, show that $\bar d\left(x\right)$ continues to be greater than $\bar u\left(x\right)$ up to the highest $x$ value ($x = 0.45$). The new results on $\bar{d}\left(x\right) / \bar{u}\left(x\right)$ and $\bar{d}\left(x\right) - \bar{u}\left(x\right)$ are compared with various parton distribution functions and theoretical calculations.
